Counter-apologetics

a set of beliefs concerning the cause, nature, and purpose of the universe, esp. when considered as the creation of a superhuman agency or agencies, usually involving devotional and ritual observances, and often containing a moral code governing the conduct of human affairs.

There are a lot of stipulations in those "especially"s and "usually"s. Does atheism (strong or not) consider the universe as a creation of superhuman agency or agencies? Of course not, just the opposite. Does atheism involve devotional and ritual observance? No. Does it prescribe a moral code? No, there are atheistic systems of morality, but there is no one system that is automatically suggested by the mere fact that one is an atheist.

But more to the point, is atheism a set of beliefs concerning the cause, nature, and purpose of the universe? Not really. Even strong atheism is one negative belief about one thing: there is no god. Even assuming strong belief in this point, that doesn't say anything at all about the actual cause, nature or purpose of the universe except in the negative.

To people who think that atheists are all of one mind about the nature of the universe, one word: Raelians.

Some people claim that atheism is a religion based on later definitions, such as

"something one believes in and follows devotedly; a point or matter of ethics or conscience: to make a religion of fighting prejudice."

Technically atheism could be considered a religion in this sense, but this wanders very far from what theists imply when they call atheism a religion, and can thus be considered equivocation. As the entry itself mentions, under this definition "fighting prejudice" is a religion. So are capitalism, football, and Star Trek. It is surely not much of an insult to be included under such a broad definition.